Metal salts of sulfonated acrylic ester polymers and lubricating oils containing thesame



Application September 26, 1955 Serial No. 536,774

15 Claims. 01. 252-33 No Drawing.

This invention relates to a lubricating oil additive composition which'when incorporated in mineral lubricating oil imparts improved detergency, viscosity index and pour point characteristics. The invention relates particularly to oil-soluble metal salts of sulfonated polymerization products of esters containing a vinyl or substituted vinyl group and to lubricating oils containing these metal salts.

\ It is known that metal sulfonates, particularly those derived by sulfonating mineral oil fractions, impart good detergent properties to mineral lubricating oils. However, it is found that in order to impart satisfactory detergency characteristics, relatively large proportions of the metal petroleum sulfonates must be employed and because of the high ratio of metal to sulfonic acid group in such sulfonates, the amount of metal added to mineral lubricating oils in order to obtain the desired detergency, is objectionably high, running as high as 2% by Weight or more in some mineral lubricating oils available on the market. The high metal content is objectionable because it has the effect of increasing engine deposits, particularly in the combustion chambers of the engine. Thus an engine operating with an oil having a high metal content is found to have an objectionable octane requirement increase during a relatively short period of operation, re sulting primarily from the increased amount of deposits in the combustion chamber.

Moreover, it is known that by adding polymerization products of various types to mineral lubricating oils it is possible to increase the viscosity index of the oil and to reduce the pour point of the oil and in order to meet requirements of engine lubricants it is often necessary not only to add materials which improve the detergency of the mineral lubricating oil but secondary additives designed to improve the viscosity index and pour point characteristics.

The object of this invention is to provide an oil-soluble, stable, additive material, which when added to minerallub'ricating oil will improve the detergency characteristics of the oil, raise the viscosity indeX of the oil and reducethe pour point of the oil, which additive material contains a relatively small amount of metal and thus, when employed in amounts necessary to impart the desired characteristics to the oil, imparts only a very small metal content to the finished oil.

A further object of the invention is to prepare mineral lubricating oils suitable for use in internal combustion engines, which oils contain the mentioned additive material, and have the desired properties of low metal content, high;detergency, improved V. I. and reduced pour point.

Another object of this invention is to produce an additive material which when added to mineral lubricating oilproduces a multi-grade lubricating oil, i. e., one suitable for use, particularly in automotive engines, under widely varying conditions of temperature, such oils being referred to as SAE SW-20 or 10-30 grade lubricating oils.

"The above objects a re accomplished by sulfonating the oil-soluble polymerization products of esters containing United States Patent atented oct- 2 1958- 2 an acrylic acid or substituted acrylic acid group, which esters have the general formula 1 C H2=(. -C -'OR where R is hydrogen or an alkyl or aryl radical containing between 1 and about 9 andpreferably between land about 6 carbon atoms and R is a monovalent hydrocarbon radical containing more than4 carbon atoms or an ether radical containing more than 4 carbon. atoms and converting the resulting sulfonated polymers into their metal salts. The resulting metal salts when added to ice mineral lubricating oils impart the desirable character- The metal salts may be istics referred to hereinabove. further reacted with a basically reacting metal compound and the resulting'complex or modified sulfonate used as the oil addition agent with the same or improved results.

Compounds which are suitable for sulfonating and which fall within the definition above given include polymerized esters of acrylic acid or alkyl or alpha aryl substituted acrylic acids and monohydric alcohols containing more than about 4 carbonatoms. The esters which when polymerized are useful in preparingthe additive compounds include the amyl, hexyl, heptyl, octyl, nonyl, decyl, lauryl, myricyl, acetyl and octadecyl esters of acrylic acid, alpha methacrylicacid, alpha phenylacrylic acidand other alpha substituted homologs of these acids. The estersmay be those prepared from normal, saturated aliphatic alcohols, although the corresponding iso and branched chain alcohols maybe employed. Moreover, ether alcohols may be substituted furthe monohydric alcohols in preparing the esters Thus, the benzyloxyethyl, cyclohexoxyethyl, amylphenoxyethyl, butoxyethyl esters may be polymerized and sulfonated in the same manner as those produced from the alcohols mentioned and the resultingsulfonicfacids converted to sulfonates invention. i m

The polymers areprepai'ed from the monomeric esters by processes well known in the art, as forexample, by heating the monomeric esters at elevated temperatures, as for example, in the range of 175 Fgto 215 F., in the presence of polymerization catalysts, such as peroxides. The method of preparing the polymers is disclosed in U. S. Patent No. 2,091,627. Generally, polymerization is continued until the average molecular weight of the polymer is within the rangeof about 5 000 to 30,000 and preferably unpolymerized monomer is removed from the resulting polymerprior to sulfonation. The polymerization may be carried out on the ester itself or the ester can be polymerized in the presence of about 1 to 3 parts or" mineral lubricating oil per part of ester. In the latter .case the polymer is obtained in oil solution.

Molecular weights shown herein are those determined following the method outlined in an article Intrinsic Viscosity-Molecular Weight Relationship for Polystyreneff by A. I. Goldberg et al., Journal of Polymer Science, volume 2, page 503, 1947.

In preparing the additive of this invention the ester polymer is sulfonated and the resulting sulfonic acid is converted into the desired metal salt. The metal salt may be used per se or it may be further treated with a basically reacting metal compound of the same or different metal underconditions to produce a sulfonate complex as will be described hereinbelow. Becauseof the fact that the ester polymers are viscous liquids or plastic solids, the polymer isdissolved in a solvent prior to sulfonation. The solvent is preferably a relatively low boiling aliphatic hydrocarbon or hydrocarbon fraction, as forexam'ple, a .paraflinidsblventhaving a boiling point range between about F. and about In place of the paraflinic solvent any solvent which is not affected by sulfuric acid during sulfonation may be employed. In the following description the method of sulfonation will be described in connection with the sulfonation of polylauryl methacrylate, however, the same conditions are applicable to the sulfonation of the other polyesters described hereina bove. One part by weight of lauryl methacrylate was dissolved in two parts by weight of a paraffinic solvent boiling between 140 F. and 170 F. solution was heated to 100 F. and 0.3 parts by Weight of 15% fuming sulfuric acid was added slowly, with stirring, over a period of approximately 30 minutes, and stirring was continued for an additional 15 minutes to insure completion of the sulfonation reaction. The sulfonated product was then neutralized with an aqueous alcoholic solution of sodium hydroxide, in which the ratio of water to isopropanol was 1 to l, and the neutralized product permitted to separate. This product separated into three phases, a water phase, an alcohol phase and a solvent phase. The waterv and alcohol phases were discarded and the sodium sulfonate which remained in the paraffinic solvent phase was recovered by evaporation of the solvent. The resulting sodiumsalt is useful per se as the detergent additive and may be added to lubricating oils to impart detergency, increase viscosity index and lower the pour point of the oil.

By the term 15% fuming sulfuric acid as used herein is meant 100% sulfuric acid containing 15% by weight of dissolved S The sodium salt produced as above may be converted into a complex or modified sulfonate by treatment with aqueous sodium hydroxide or other basically reacting metal inorganic compound at elevated temperatures. Preferably the aqueous solution of basic compound will be added slowly over a period of 30 minutes or more to a solvent or lubricating oil solution of the sulfonate at a temperature of about 150-350 F. When the complexing is effected in the presence of solvent at reflux system is arranged so that water being vaporized with the solvent is removed by means of a water trap in the reflux line. Heating is then continued until all the water has been removed. Following removal of the water, the solvent solution is filtered and then evaporated to remove solvent.

In case it is desired to produce other metal salts of the sulfonated polyesters, as for example, the calcium salt, the solvent solution of sodium sulfonate before evaporation of solvent is metathesized with a water-soluble calcium salt, as for example, calcium chloride. Following phase separation and removalof aqueous phase, the solvent phase may then be evaporated to. obtain the calcium sulfonate or, as described above in connection with the sodium salt, the calcium salt in solventsolution may be complexed with additional calcium oxide or hydroxide or other basically reacting metal inorganic compound to produce the complexed or modified calcium sulfonate.

In order to clarify the disclosure herein, the terms acrylic acid and acrylic acid esters are used in their vbroad sense to designate the unsubstituted as well as the various hydrocarbon substituted acrylic acids and acrylic acid esters described.

Methacrylate type polymers and various polyesters of the type described herein are available commercially in the formof an oil solution containing from about 1 to 3 parts of a neutral oil per part of polymer. It is found that these oil solutions of polymer may be sulfonated in the same manner and under the' same conditions described above for the polymer itself and with substantially the same results. Moreover, the resulting sulfonic acids may be converted into their metal salts and these may be further converted into complex metal sulfonate in the manner described for those produced directly from the polyesters.

Metals which may be employed to produce the metal sulfonates of this invention are preferably the alkaline earth metals, calcium, magnesium, strontium and barium; the alkali metals, sodium, lithium and potassium; and lead, although other metals are useful. Such other metals include copper, nickel, cobalt, iron, manganese and thelike. The alkali metal sulfonates are preferably produced by direct neutralization of the sulfonated polyesters with the corresponding alkali metal hydroxide, as for example, sodium hydroxide, potassium hydroxide or lithium hydroxide. The polyvalent metal salts may be produced by direct neutralization of the sulfonated polyesters, how'- ever, they are preferably produced by metathesis following the procedure outlined above in' connection with the preparation of the calcium sulfonate.

The preparation of the complex or modified sulfonates described hereinabove is simplified if the metal sulfonate is recovered from its solvent solution and dissolved in mineral lubricating oil prior to the complexing. Thus, the metal salt of the sulfonated polyester dissolved in approximately 3 parts of oil may be readily complexed by heating the oil solution of metal sulfonate to a temperature preferably above the boiling point of water, as for example, 220300 F. and while agitating the oil solution, adding an aqueous solution or slurry of the basically reacting metal compound which is to be used for complexing. The aqueous solution or slurry is added slowly over a period of at least about 30 minutes and heating continued for an additional 15 to 20 minutes or longer to effect the removal of water and complexing. During this period the water is expelled, leaving a modified sulfonate containing excess basically reacting inorganic compound in the form of a complex or stable dispersion in the oil solution. Methods of preparing complexes of sulfonic acids which are applicable to sulfonic acids of this invention are described in U. S. Patent No. 2,501,732.

Basically reacting metal compounds which may be employed include the oxides, hydroxides, carbonates and bicarbonates of the metals disclosed above as being useful in the preparation of sulfonates. Generally it is desirable that the metal of the basically reacting metal compound be the same as the metal of the sulfonate, although the metals may be different. For example, a barium sulfonate may be complexed with strontium hydroxide.

The complex or modified sulfonates described herein appear to be and may be defined as permanent dispersions of basically reacting metal inorganic compound with sufficient sulfonate to serve as dispersing agent for the basic compound.

Generally in preparing the complex sulfonates of this invention between about 0.2 and 2 equivalents of the basically reacting metal inorganic compound per equivalent of metal sulfonate will be employed and in most cases all or nearly all of the'basic compound will be complexed thus giving complex or modified sulfonates in which the ratio of total metal to metal of the metal sulfonate will be between about 1.2 and 3 to l. H

Lubricating oils are prepared from the'sulfonates and complex sulfonates described herein by dissolving between about 0.2% and 7% by weight of the sulfonate or complex sulfonate in mineral lubricating oil. No special technic is required in preparing these oil solutions because the additive materials are oil soluble, however, mixing is facilitated if the additive is incorporated in the oil at elevated temperatures, as for example, at temperatures of 200-325" F. The resulting lubricating oils prepared with metal sulfonates will have metal contents varying between about 0.001% and about 0.20%

by weight and those prepared with complex sulfonates will have metal contents between about 0.002 and about 0.3% by weight. Generally the metal contents will be between about 0.01% and 0.1%.

Lubricating oils which may be used in preparing the finished oils of this invention includes substantiallyall types of mineral lubricating oils of both parafiinic and naphthenic types. Thus, the additive material is found to'be effective in solvent treated parafiinic type mineral lubricating oils having viscosity indices between about and about 100, although oils of lower V. I., e. g., 5- :60 are advantageously employed because the additives of 5 this invention are found to raise the viscosity indices of such oils into a range which is entirelysatisfactory-for automotive engines. In the case of all of these oils the detergency is greatly increased, the viscosity index is improved by the addition of the oil-soluble metal sulfonates or complex sulfonates derived from the polyesters described herein. In any oils of objectionably high pour point it is found that the pour point is lowered to a desirable degree by such additions.

In determining the detergency of mineral lubricating oils containing the additives of this invention tests have been carried out on the finished oils in Lauson single cylinder standard test engines. In this test, which is referred to herein as the Lauson engine test, the engine is operated for a total of 72 hours under a load of about 2.1 H. P. with a coolant temperature of about 160 F. and an oil temperature of about 150 F. These conditions are designed to simulate passenger car service. At the end of the test period the cleanliness of the engine is observed and given a numerical detergency rating between and 100%, where 100% indicates a perfectly clean engine. Thus, a detergency rating of 100% would indicate that there were substantially no lacquer or varnish-like deposits within the engine.

Although mineral lubricating oils containing additives of this invention have the desired characteristics referred to herein, it is sometimes desirable to add a second additive material which imparts anti-corrosion characteristics to the mineral lubricating oil. Anti-corrosion agents which cooperate with the sulfonates and complex sulfonates of this invention to produce outstanding lubricating oils include the following materials which are known to be anti-corrosion agents, but which have been found to be particularly eflective in maintaining proper anti-corrosion conditions in engines when used in conjunction with the sulfonates and modified sulfonates described herein.

One form of anti-corrosion agent which may be employed is an oil-soluble metal salt of the acidic reaction product obtained by reacting phosphorus pentasulfide or phosphorus pentoxide with an alcohol. The preferred reaction products are those obtained with phosphorus pentasulfide. These materials are represented by oilsoluble metal salts of alkyl thiophosphates such as zinc dioctyl dithiophosphate or the corresponding calcium or other polyvalent metal salt. Salts of reaction products of phosphorus pentasulfide and aliphatic and cycloaliphatic alcohols having more than about 6 carbon atoms per molecule are preferred.

Other anti-corrosion agents which may be employed in conjunction with the sulfonates of this invention include metal salts of phenols and phenol sulfides. These agents are included in the group of agents which may be referred to as oil-soluble metal salts of high molecular weight non-carboxylic weak acids having ionization constants below about 10 These salts which are described in U. S. Patent No. 2,280,419 are suitable in that they cooperate with the additive of this invention to produce oils having all of the desired characteristics.

Another class of anti-corrosion agents which may be employed includes the oil-soluble metal salts formed by reacting phosphorus pentasulfide with hydrocarbons. Such materials and methods for their preparation are described in U. S. Patent No. 2,316,082.

Another type of anti-corrosion agent which may be employed to impart the desirable anti-corrosion characteristics consists of the oil-soluble metal salts of phosphinic or phosphonic acids obtained by treating hydrocarbons with elementary phosphorus and subsequently forming the metal salts of the reaction products. Compounds of this type are described in U. S. Patent No. 2,311,305.

Oil-soluble salts of the condensation products obtained by reacting a hydrocarbon substituted phenol with alow molecular weight aldehyde such as formaldehyde are out standingintheir ability tocooperate withthe sulfonates and complex sulfonates of this invention to produce oils having extremely good anti-corrosion and detergency characteristics. These compounds are described and methods of their preparation are given in U. S. Patent No. 2,250,188.

Metals which may be used in the preparation of the anti-corrosion agents include the alkaline earth metals, calcium, barium, strontium and magnesium and the polyvalents metals, zinc, aluminum, tin, copper, iron, nickel, mercury and chromium. In some instances alkali metal salts or soaps may be employed when they are sufficiently soluble in oil.

In employing the anti-corrosion agents, in the order of 1% of the constituent ordinarily will be adequate, such as 0.5% or 1.5%, or possibly less, e. g., 0.2%, for some uses. Although not more than 3% or 5% based on the final product is necessary for most uses, a number of modern heavy duty engines require more, up to 8% or 10%, and amounts up to 20% or more may be desirable for some uses. The anti-corrosion agents are conveniently employed in the form of concentrates containing 30 to 60% additive dissolved in lubricating oil. They may also be employed in the form of concentrates also containing the sulfonates of this invention. In this case, the total additive concentration may be about 30 to 60%, with the modified sulfonate preferably in slight excess over the anti-corrosion agent.

Example I A solution of parts of a commercial polymerized lauryl methacrylate having a molecular weight of approximately 20,000 in 200 parts of a paratfinic hydrocarbon solvent, having a boiling point within the range of about F. to about F., was heated to 100 F. and to the heated solution 33 parts by Weight of 15% fuming sulfuric acid was added slowly, over a period of approximately 45 minutes, withvigorous agitation. The reaction mixture was maintained between 100 F. and 110 F. for an additional 30 minutes. Suificient sodium hydroxide dissolved in equal parts of isopropanol and water to give a 10% solution of NaOH was then added and agitation continued until neutralization was eflected. The neutralized product was permitted to settle and the aqueous and alcoholic phases were removed, leaving a solvent phase containing the sodium salt of sulfonated polylauryl methacrylic acid. The solvent solution was washed with a 50% solution of isopropanol in water to remove inorganic materials.

One portion of the solvent solution was evaporated to recover the sodium sulfonate. This material will be referred to hereinafter as Product A.

A second portion of the solvent solution of sodium sulfonate was converted into the calcium salt by metathesis with calcium chloride. An amount of calcium chloride equivalent to the sodium sulfonate salt, in the 7 form of a 10% aqueous solution, was added and the mixture vigorously agitated for approximately 30 minutes. The aqueous phase was permitted to separate and was discarded. The calcium sulfonate salt was recovered by evaporating the hydrocarbon solvent. This calcium sulfonate will be referred to hereinafter as Product B.

A third portion of the solvent solution of sodium sulfonate was converted into the barium salt, using barium chloride and following the procedure outlined for the preparation of calcium salt. The recovered barium sulfonate will be referred to as Product C.

A fourth-portion of the solvent solution of sodium sulfonate was converted to the strontium salt by metathesis with strontium chloride in the manner described for the calcium sulfonate. The recovered strontium sulfonate. salt will be referred to as Product D.

A fifth portion of the solvent solution of sodium sulfonate was converted into the lead salt by metathesis with lead nitrate following the procedure outlined for the calcium salt. The recovered lead sulfonate will be readded over a period of approximately 30 minutes while ferred to as Product E. vigorously agitating the mixture. Following completion A portion of the lead sulfonate, Product E, was conof the sulfonation, the product was neutralized with soverted into a lead sulfonate-lead oxide complex by disdium hydroxide dissolved in isopropanol and water. After solving 7 parts of Product E in parts of a mineral lubri- 5 separation of the aqueous and alcoholic phases, the hydrocating oil of SAE 5 grade. The resulting oil solution was carbon sol-vent phase was separated into two portions, one heated to a temperature of 300 F. and to the heated soluof the portions was evaporated to recover the sodium sultion was added 1.25 parts by weight of lead oxide in the fonate and the second portion was metathesized with lead form of a slurry in 5 parts by weight of water. This addinitrate and the methathesized product evaporated to re tion was made slowly, over a period of approximately 14} cover the lead sulfonate. A portion of the lead sulfonate minutes, with vigorous agitation. The resulting product so recovered was dissolved in 2 parts of mineral lubricatwas heated to 325 F., and filtered through a filter aid. ing oil and heated with 2- equivalents of lead oxide per The filtered oil solution, consisting of a concentrate of equivalent of metal sulfonate in the presence of a small lead oxide-lead sulfonate complex in oil will be referred amount of Water to form the lead oxide-lead sulfonate to as Product F. complex.

Lubricating oils were prepared by dissolving each of Oils containing each of the above sulfonates were found the above products (Products A to F, inclusive) in minto have good detergencies, improved viscosity indices and eral lubricating oil of SAE grade having a viscosity lowered pour points as compared with the base oil.

index of 86 and a pour point of 0 F. This base oil had a detergency rating in the Lauson engine test of 35. The 20 Example V amount of metal sulfonate employed was in each case the polymerized cetyl alphamethaerylate, having a e amount necessary to impart a metal content of about lar Weight of 25,000, s at d in t nner de- 0.01% with the exception that in the case of Product F scribed in EXample I and the sulfonated product neu the metal content of the finished oil was 0.02%. Each of iraliled h Sodium hydroxide. The r sulting Sodium the oils operates satisfactorily in the Lauson engine and SulfOIlate Was Converted into the eerrespending lead, $111- in this test the detergencies are all above 80. Moreover, f n y metathesis i h l ni r T p these oils have viscosity indices greater than 105 and pour When dissolved in an SAE 30 selvel'lt extraeied Paraffinic points of -20 F. or low r, mineral lubricating oil in an amount to give an oil having a lead content of 0.05 by Weight was found to give good detergency, improved viscosity indices and lowered pour A polylauryl methacrylate of approximately 20,000 point as compared with the baseoil.

molecular weight was sulfonated, the sulfonated product E 1 VI converted into its lead salt, and the lead sulfonate comxamp 8 Example II 30 plexed with lead oxide as described in Example I. The M Lubricating Oils Were P p With a SOdiIlIII Salt f a product corresponded to Product F of that example. Sulfonated p y Y methacrylate, having a molecular Lubricating oils containing various concentrations of Weight of appfeXimalely 20,000, y blending the Oil @011? this complex sulfonate Were prepared and evaluated and centrate of the sulfonate With an 86 V. I. paraflinic oil of for purposes of comparison lubricating oils containing SAE 30 g The Sodium Sulfonfite Was P p various proportions of unsulfonated polylauryl meth- W lIhe manner described in Example I and corresponds to acrylate were also prepared and evaluated using the same Product A Of that example For comparison an Oil Was tests. prepared using the unsulfonated polymer in approximately Data regarding these oils together With the correspondthe same proportion. Test results on these oils were as ing data for the base oil are shown in the following table. ll s The base oil was a solvent-extracted Western paraflinic lubricating Oil Of SAE 30 grade. Metal Pour Deter- Oil Con- V. I. Point, gency,

tent, F. Per- Metal Pour Deter- Percent cent Oil Con- V. I. Point, gcncy,

tent, F. Per- Percent cent B1150 O 86 0 35 75% unsuli. polymer 110 20 .0% Na Sulf. polymer 0026 105 20 79 Base on .87% Na Sulf. polymer 0048 120 20 82 1.75% unsulf. p0lyrner .68% Na Sulf. polymer 0034 108 20 2.0% unsulf. polymer i unsullfipolylzmernn DIIDSU. 0 mella. t +085]? 1 y Example VII i g sulftpolymer Pbo M 86 55 Lubrlcatlng oils were made by blending a calciumsalt 3.75 Pb snlf. polymer PbO 125 15 of a sulfonated polymer prepared 1n the manner described in Example I and corresponding to Product B of. that Exam le III eXample, in a solvent treated SAE 5 grade naphthenic oil f28's 't'de. Product C of Example I, converted to the barium hy- 0 V1 6081 y m X Data Obtamed on these 0118 and droxi-de-barium sulfonate complex by treatment of the sulfonate in naphtha solution with an aqueous slurry of follows. barium hydroxide at a temperature of 230 B, When dissolved in a naphthenic lubricating oil of 30 V. I. to imon 552?" part a metal content of 0.05% gives an oil of about 110 V. I. having good detergency. Base on 20 2s +0.850% Ca sulf. polymer. 81 E l [I] +1.125% Ca sulf. polymer. 103 +1.500% Ca sulf. polymen 111 A concentrate consisting of 50% of a polymerized lauryl +1'875% 0a Sum polymer 122 methacrylate, having a molecular weight of about 15,000, 70 in a neutral oil was dissolved in 2 parts of parafiinic hydro- Example VIII carbon solvent per part ofconcentrate and the resulting Polymerized butoxyethyl acrylate having a molecular solution treated with 53% by weight of 15% fuming sulweight of about 15,000 was sulfonated as described in Exfuric acid, based on the. polymerized lauryl methacrylate, ample I and the product neutralized with barium hydroxat a temperature of about 110 F. The fuming acid was ide. This product when added to an SAE 30 solvent exon an oil containing the unsulfonated polymer were as- 9 tracted parafiinic mineral oil in an amount to give a barium content of 0.08% gives an oil with good detergency and improved V. 1. characteristics.

The above examples are illustrative but are not to be taken as limiting the invention to the particular metals and the particular sulfonated polymers described since the other metals and other polyesters described hereinabove when substituted for the specific metals and specific polyesters shown in the examples give sulfonates and complex sulfonates which impart the desirable characteristics of high detergency, high viscosity index and low pour point to mineral lubricating oils.

This application is a continuation-in-part of application Serial Number 355,408 filed May 15, 1953, now abandoned.

I claim:

1. A lubricating oil comprising mineral lubricating oil in major amount containing between about 0.2% and about 7% by weight of a metal salt of a sulfonated polymerized ester, said ester having the formula in which R is a radical selected from the class consisting of hydrogen and alkyl and aryl radicals containing between about 1 and about 9 carbon atoms and R' is a monovalent radical selected from the class consisting of hydrocarbon and ether radicals containing more than 4 carbon atoms and obtained by sulfonating said ester with a sulfonating agent in an amount of one-third on the weight of the polymer, the polymeric ester having an average molecular weight of about 5000 to 30,000.

2. A composition adapted for addition to mineral lubricating oil comprising a complex sulfonate consisting of between about 0.2 and 2 equivalents of a basically reacting metal inorganic compound of the class consisting of metal oxides, hydroxides, carbonates and bicarbonates and 1 equivalent of metal sulfonate, said metal sulfonate being a metal salt of a sulfonated polymerized ester, said ester having the formula in which R is a radical selected from the class consisting of hydrogen and alkyl and aryl radicals containing between about 1 and about 9 carbon atoms and R is a monovalent radical selected from the class consisting of hydrocarbon and ether radicals containing more than 4 carbon atoms and obtained by sulfonating said ester with a sulfonating agent in an amount of one-third on the weight of the polymer, the polymeric ester having an average molecular weight of about 5000 to 30,000.

3. A lubricating oil comprising mineral lubricating oil in major amount containing between about 0.2% and about 7% by weight of a complex sulfonate, said complex sulfonate being a permanent dispersion of between 0.2 and 2 equivalents of a basically reacting metal, inorganic compound of the class consisting of metal oxides, hydroxides, carbonates and bicarbonates with 1 equivalent of metal sulfonate, sufiicient to serve as dispersing agent for said basically reacting metal compound, said metal sulfonate being a metal salt of a sulfonated polymerized ester, said ester having the formula in which R is a radical selected from the class consisting of hydrogen and alkyl and aryl radicals containing between about 1 and about 9 carbon atoms and R is a monovalent radical selected from the class consisting of hydrocarbon and ether radicals containing more than 4 carbon atoms and obtained by sulfonating said ester with a sulionating agent in an amount of one-third on the weight 10 of the polymer, the polymeric ester having an average molecular weight of about 5000 to 30,000.

4. A composition adapted for addition to mineral lubricating oil in major amount, said composition comprising a metal salt of a sulfonated polymerized ester, said ester having the formula in which R is a radical selected from the class consisting of hydrogen and alkyl and aryl radicals containing between about 1 and about 9 carbon atoms and R is a monovalent radical selected from the class consisting of hydrocarbon and ether radicals containing more than 4 carbon atoms, the polymeric ester having an average molecular weight of about 5000 to 30,000, and the sulfonated polymeric ester being obtained by sulfonation with a sulfonating agent in an amount of one-third on the weight of the polymer.

5. A lubricating oil according to claim 1 in which said metal is an alkaline earth metal.

6. A lubricating oil according to claim 1 in which said metal is an alkali metal.

7. A lubricating oil according to claim it in which said metal is lead.

8. A lubricating oil according to claim 3 in which said basically reacting metal inorganic compound is an alkaline earth metal hydroxide and said metal of the metal sulfonate is an alkaline earth metal.

9. A lubricating oil according to claim 3 in which said basically reacting metal inorganic compound is a lead oxide and said metal of the metal sulfonate is lead.

10. A composition adapted for addition to mineral ludbricating oil consisting essentially of alkaline earth metal polylauryl methacrylate sulfonate obtained by sulfonating said methacrylate with a sulfonating agent in an amount of one-third on the Weight of the polymer.

11. A composition adapted for addition to mineral lubricating oil consisting essentially of alkali metal polylauryl methacrylate sufonate obtained by sulfonating said methacrylate with a sulfonating agent in an amount of one-third on the weight of the polymer.

12. A composition adapted for addition to mineral lubricating oil consisting essentially of lead polylauryl methacrylate sulfonate obtained by sulfonating said methacrylate with a sulfonating agent in an amount of onethird on the weight of the polymer.

13. A lubricating oil comprising mineral lubricating oil in major amount containing between about 0.2% and about 7% by weight of an alkaline earth metal polylauryl methacrylate sulfonate obtained by sulfonating said methacrylate with a sulfonating agent in an amount of one-third on the weight of the polymer.

14. A lubricating oil comprising mineral lubricating oil in major amount containing between about 0.2% and about 7% by weight of lead polylauryl methacrylate sulfonate obtained by sulfonating said methacrylate with a sulfonating agent in an amount of one-third on the weight of the polymer.

15. A lubricating oil comprising mineral lubricating oil in major amount containing between about 0.2% and about 7% by weight of complex sulfonate, said complex sulfonate comprising between about 0.2 and 2 equivalents of an alkaline earth metal hydroxide and 1 equivalent of an alkaline earth metal polylauryl methacrylate sulfonate obtained by sulfonating said methacrylate with a sulfonating agent in an amount of one-third on the weight of the polymer.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LUBRICATING OIL COMPRISING MINERAL LUBRICATING OIL IN MAJOR AMOUNT CONTAINING BETWEEN ABOUT 0.2% AND ABOUT 7% BY WEIGHT OF A METAL SALT OF A SULFONATED POLYMERIZED ESTER, SAID ESTER HAVING THE FORMULA
 2. A COMPOSITION ADAPTED FOR ADDITION TO MINERAL LUBRICATING OIL COMPRISING A COMPLEX SULFONATE CONSISTING OF BETWEEN ABOUT 0.2 AND 2 EQUIVALENTS OF A BASICALLY REACTING METAL INORGANIC COMPOUND OF THE CLASS CONSISTING OF METAL OXIDES, HYDROXIDES, CARBONATES AND BICARBONATES AND 1 EQUIVALENT OF METAL SULFONATED POLYMERIZED ESTER, SAID ESTER METAL SALT OF A SULFONATED POLYMERIZED ESTER, SAID ESTER HAVING THE FORMULA 